During construction of walls (or other types of surfaces) to develop a video game level, gaps and voids may be produced by walls that do not properly intersect. For quality assurance, processes may be executed to check the level and identify such imperfections and take correction action (e.g., adjust wall position and orientation for an appropriate fit). By methodically “rubbing” a game character against each and every simulated wall, gaps may be visually detected if a portion of the game character or if the entire character falls into such a void. By executing such testing, probability is reduced that a character may become embedded in a wall during game play and take away from the enjoyment of the game experience.